Although conventional hydrophilic polymer or hydrogel lenses are useful and effective, some problems do present themselves, from time to time. For example, conventional hydrophilic contact lenses can be associated with lens wearer discomfort and/or eye irritation, which can result in the lens wearer perceiving that his/her eye is dry. “Dry eye” phenomenon has been treated by lens wearers with eye drops and/or lubricants.
Silicone hydrogel contact lenses are a commonly used type of contact lenses. Silicone hydrogels generally have higher oxygen permeabilities than conventional hydrogel contact lenses. In addition, silicone hydrogels typically have more hydrophobic materials than conventional hydrogel contact lenses, and therefore, additional processing steps or formulation ingredients are necessary to produce contact lenses with wettable surfaces compared to conventional hydrogel contact lenses.
Producing wettable silicone hydrogel contact lenses while addressing commercial realities, such as low costs of goods, good clinical performance, and high processability, remains a challenge.